Idle air bypass means



June 1, 1965 J. T. w. MOSELEY 3,186,692

IDLE AIR BYPASS MEANS Original Filed May 9, 1958 3 Sheets-Sheet 1INVENTOR. JIMESZWMOSELH wmWM/ June 1, 1965 J. 1'. w. MOSELEY 3,186,692

IDLE AIR BYPASS MEANS Original Filed May 9, 1958 3 Sheets-Sheet 2 lNVENTOR.

ATTO/P/V'y firms TIM/Mayan Jime 1, 1965 J. T. W. MOSELEY IDLE AIR BYPASSMEANS Original Filed May 9, 1958 CHOKE VALVE puuyopav I NORMAL OPERATINGS TEMPERATURE I u; 11- i 1 a CHOKE VAL l/E OPE/V/ll/G- 01? ENG/AlfTEMPt'EATl/IPE 70741 fall-'41P FZOWl/Y GEM.

076 52 CURVES BASED ON .D/FFt'PE/VT 3 Sheets-Sheet 5 ova/ 5 VAL 1/5FULLY OPE/V 3 CHOKE VALVE OPEN/N6 0E /V6//V TEMPfPA TURE INVENTOR.JZIME: KHZ/M0554 5r A TTOIP/VEY United States Patent 3,186,692 IDLE AIRBYEASS MEANS James T. W. Moseley, Glendale, Califi, assignor to HolleyCarburetor Company, Warren, Mich a corporation of Michigan Continuationof application Ser. No. 734,159, May 9, 1958. This application June 2!H62, Ser. No. 295,822 2 Claims. (Cl. 261-32) eration has proved to beunsatisfactory especially in those situations were the engine has notreached normal operating temperatures and the ambient temperature 1slow. When a carburetor of this type is idled in cold weather, themoisture content of the air drawn around the cracked throttle frequentlycondenses and freezes adjacent to and on the upper surface and edges ofthe throttle valve due to the cooling eflfect of the air flowing pastthe throttle. The ice which is so formed may clog the idle fuel portsand cause engine stalling.

Various designs have been proposed to eliminate this icing, such asartificial heating of the carburetor by electrical means and idle airbypass means which obtain the idle air from within the induction passageanterior to the throttle and discharge it posterior to the throttlevalve.

However, none of these proposed general solutions eliminated theproblem. The artificial heating is a costly and unpredictable method andthe present idle air bypass means do not actually deal with the problemthey purport to.

It is well known that an engine must idle at a higher r.p.m. during coldengine operation in order to continue to be self-sustaining. This meansthat more air must be introduced during that period than at idleoperation when the engine has reached normal operating temperatures. Allprior idle air bypass systems were of the fixed Orifice type; that is,the amount of air allowed was determined for a certain ambienttemperature condition. Since the temperature selected would have to beindicative of summer driving and the ambient temperature once the enginereached normal operating temperatures, the amount of air introducedwould have to be less than that required by cold engine runs with lowambient temperatures.

In order to circumvent this apparent inconsistency be tween the originalproblem and proposed solutions, temperature controlled fast idle camshad to be employed in order to supply the additional air for fastidle-cold engine operation. Since the fast idle cams are used to holdthe throttle valve open a certain amount, it is obvious that the priorsolutions did not overcome the problem because they are almost entirelyinelfective during the precise range of engine operation that the icingproblem is at its worst.

Accordingly, an object of this invention is to provide means which willsupply sufficient amounts of idle air for all conditions of engine idleoperation.

More specifically, the object is to automatically provide a greateramount of air during cold engine operation than at normal engineoperating temperatures without opening the throttle valve.

Other objects and advantages will become apparent a illustrations inwhich:

FIGURE 1 illustrates in perspective a carburetor embodying theinvention;

FIGURE 2 is a side elevational view, with portions thereof broken awayand in cross-section, taken in the direction of the arrows of FIGURE 1.FIGURE 2 also illustrates a portion of the carburetor aircleaner and theengine;

FIGURE 3 is a fragmentary cross-sectional view of the carburetor takensubstantially on line 3-3 of FIGURE 2;

FIGURE 4 is an enlarged fragmentary cross-sectional View of certaindetails illustrated in FIGURE 2;

FIGURE 5 is a cross-sectional view taken on line4-4 of FIGURE 4;

FIGURE 6 is an exploded view in perspective of some of the elementsillustrated in FIGURE 2;

FIGURE 7 is a schematic illustration of a modification of the invention;

FIGURE 8 is a graph illustrating the characteristic performance curvesof the modification;

FIGURE 9 is a schematic illustration of the preferred embodiment of theinvention shown by FIGURE 2;

FIGURE 10 is graph illustrating the characteristic performance curves ofthe preferred embodiment of the invention;

FIGURE 11 is a chart of the data used in preparing the graphs of FIGURES8 and 10.

Referring now in greater detail to the illustrations, FIGURE 1illustrates a carburetor 10 having a throttle body 12 above which islocated an air intake passage 14 having a choke valve 16 therein. Achoke shaft 18 is secured to the choke valve and has at one end thereofsecured to it a lever 26 which is adapted to be rotated by a rod 22which is pivotally secured at its other end to an arm 24.

A choke operating assembly generally indicated at 26 contains the usualcoiled bimetallic thermostat 27, one end of which is adapted to rotatearm 24 in accordance with temperature and engine operating requirements.

FIGURE 2, a cross-sectional view taken on line 2-2 of FIGURE 1, showsthe air cleaner 28 fixed to the carburetor 1% and substantiallyenclosing therein the air intake 14. The carburetor body 12 containsinduction passages 30 and 32 (FIGURES 2 and 3), each having a main fuelnozzle 34, a venturi 36, an idle fuel transfer port 38, idle fuel portand a throttle valve 42 mounted on a shaft 44 which is common to bothinduction passages. Both the main nozzle and idle fuel port recive theirfuel through suitable conduitry from the chamber of fuel bowl 46.

The above described structure is so well known in the art that any oneskilled in the art will readily recognize it.

A constantly open idle air bypass system is illustrated by a verticalconduit 4-3, one end 5!) of which is open to the chamber 52 generallyformed by the air cleaner 28. The other end of conduit 4% is incommunicationwith a laterally extending conduit 54 and the flow of airtherethrough is adapted to be controlled by an adjustable needle valve56 and coacting metering seat 58. A second laterally extending conduit60 which is perpendicular to conduit 54 and in communication therewithhas at its opposite ends vertical conduits 62 and 64 which in turncommunicate with the induction passages 39 and 32 posterior to thethrottle valves 42 by means of ports 66 and 68.

In addition to the constantly open air bypass system described above, asecond variable air bypass communicates with conduit 54 posterior toneedle valve 56 and seat 58. This variable bypass may be comprised of avertically extending conduit '70 having a substantially concentricmeter- Patented June 1 1965 1 June 1, 1965 F. M. WINCHELL THERMOMETERFIXING MACHINE AND METHOD OF FIXING Filed May 6, 1963 3 Sheets-Sheet 1Frederic M. Mnche/l IN VEN TOR.

1. A CONTROL MECHANISM FOR AN INTERNAL COMBUSTION ENGINE CARBURETORHAVING A THROTTLE VALVE AND AN INDUCTION PASSAGE THEREIN, SAID INDUCTIONPASSAGE BEING NORMALLY SUBSTANTIALLY CLOSED BY SAID THROTTLE VALVE, SAIDCONTROL MECHANISM COMPRISING A CHOKE VALVE AND A CHOKE SHAFT IN SAIDINDUCTION PASSAGE, THERMOSTAT MEANS TENSIONED FOR VARIABLY OPPOSING THEOPENING OF THE CHOKE VALVE AS A FUNCTION OF ENGINE TEMPERATURE, MEANSFOR DELIVERING IDLE FUEL DOWNSTREAM OF SAID THROTTLE, CONSTANTLY OPENIDLE AIR BYPASS MEANS DISCHARGING AIR ONLY DOWNSTREAM OF SAID THROTTLEVALVE, MEANS INCLUDING A METERING VALVE FOR SUPPLEMENTING SAID IDLE AIRBYPASS MEANS WITH ADDITIONAL AIR, MEANS NORMALLY BIASING SAID METERINGVALVE IN A DIRECTION SO AS TO CLOSE SAID SUPPLEMENTING MEANS, ACTUATINGMEANS SECURED TO ONE END OF SAID CHOKE SHAFT FOR ROTATION THEREWITH,CONNECTING MEANS OPERATIVELY ENGAGING SAID ACTUATION MEANS AND SAIDMETERING VALVE, SAID ACTUATION MEANS BEING POSITIONED BY SAID CHOKESHAFT SO AS TO CAUSE SAID CONNECTING MEANS TO OPEN SAID METERING VALVEAGAINST SAID BIASING MEANS UPON CHOKE CLOSING MOVEMENT.